Credit Score Management

If I apply for a new credit card (visa signature) but cancel my ancient visa card? If my current credit score is 750, what will be my score after doing so?

I came across some programs offered by, ex-bankers, ex-credit bureau agents that offer tactics and software that enable you to repair your credit. They claim to be able to make a new credit file. Anyone know if they work? What happens to your ancient credit file?

I need to improve my credit score by 4 points for a loan. Is there anyway to quickly improve your credit score over a few weeks\months?
If I pay off the remainder of some of my student loans could my credit score jump immediately?

I need to rebuild credit history but I don’t want a ton of credit inquiries dragging my score down…

i have really terrible credit and i wanna fix my credit.i cannot get a cell phone with my terrible credit or a loan.so does anyone know any excellent and low cost credit repair services.plz answer my question.